Bus systems and subbus systems are used in motor vehicles, electronic systems of the motor vehicle having a bus node and communicating with one another via bus connections in order to perform control operations and/or to exchange data. If the motor vehicle is not used, a large number of these electronic systems are switched into a sleep mode in order to reduce as far as possible the overall power consumption of the motor vehicle and therefore the power drain from a motor vehicle battery.
If a function of an electronic system is requested by, for example, activating a pushbutton key of the electronic system, this electronic system is switched from the sleep mode into an operating mode in order to carry out the function. For this purpose, the electronic system has a wakeup circuit which brings about switching from the sleep mode into an operating mode. Likewise, this electronic system can be woken up by a wakeup signal from another electronic system of the motor vehicle, which signal is transmitted from bus node to bus node via the bus system.